farmer



(No Model.) v 1 n 2 sheets-sheet 1. M. G. FARMER.

TELEPHONE.

No. 351,258. n vPaentd Oct. 19, 1886.

N4 PETERS. Pham-Lnhogqphw. Waington, D. C.

2 Sheets-Sheet 2.

(No M0881.)

M. G. FARMER.

TELEPHONE.

* 110.851.258. Patented 001. 19, 1888.-

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UNITED STATES PATENT OEEIcE.

MOSES G. FARMER, OF NEV YORK, N. Y.

TELEPHONE..

SPBCEICATION forming part of Letters Patent No. 351,258, date-c". October 19, 1886.

Application filed June ll, 18516.

To all whom it may concern:

Be it known that I, Moses G. FARMER, a citizen of the United States, and a resident ol New York, in the county and State of New York, have invented certain new and useful improvements in Telephones, ot' which the following is aspecilcation, reference being had to the drawings accompanying and forming a part of the same.

My invention consists in a novel form of telephonefreceiver, constructed with a view to securing more pronounced vibrations of the diaphragm, and a consequent more audible reproduction of the sound-waves transmitted as d electrical impulses or undulations over a telephone-line.

The ordinary i'orm of telephone receiver has a magnetic diaphragm; but in lieu ot' this a non-magnetic diaphragm may be en'iployed, to which a magnetic armature is attached. My apparatus belongs to this latter class of telephones; butin lieu of an ordinary magnet and armature carried by the diaphragm it has a series or system of coils, forming a compound helix, in which is suspended a core of special construction, which is attached to the diaphragm..

An apparatus to embody these features with the general. arrangement above stated may obviously be constructed in many diiiercnt ways. In illustrating my invention', however, I shall confine myself toathe description of the best and most practicable form of apparatus which is at present known to me, and which contains in itself certain features that are novel and that contribute tothe eiliciency and usefulness of the instrument.

rlhe accompanying drawings show the details of this instrument, Figure 1 being a horizontal section of the device, taken just above the coils, Fig. 2, a central vertical section of the same, Figs. 3 and 4t being views in elevation of the parts that make up the armature and core; and Fig. 5 is a diagram of the circuits.

A A are two circular brass plates secured together by the rods B B and made fast to a stand or base, C. Between the two plates or heads A A' are the coils comprising the compound helix, of which the inner coil, D, is of comparatively coarse wire with but few turns or layers, while the other coil, E, is of liner wire with a large number of turns or layers.

Serial No. 204,938. (No model.)

The outer coil, E, may lit loosely over the coil D.

The coilD surrounds a stationary tubular core composed of the sof`t-iron sections F F. The sections F are shouldered at each end and held apart by the brass or nonmagnetic ringsy otherwise, so as to contain ta greater mass ofL iron at their upper ends. `They are of a diameter to lit loosely within the sections F, and are separated from each other by interposed rings of a non-magnetic metal, g. The armatures are secured to the tube H and the sec tions F placed over them in building up the core, so that the heads or iianges g will be contained in the spaces between the sections F, and be capable ot' such movement therein as will permit a limited longitudinal movement of the tube H through the core.

rlhe :upper end ot' the tube H is secured to the center of a diaphragm, l, which is contained in any proper kind of case-for exam-` ple, a recessed and perforated. block, J, of hard rubber-the diaphragm being confined in place by a screw-threaded cover, K, provided with a mouthpiece, L, and fitting down into the recess and the upper side of the block J. The block J is adjustably mounted upon the plate A by the screw-rods N L and binding-nuts m, by means of which it may be slightly raised or lowered to secure the best adjustment of the tube H and armatures G, with reference to the sections F of the stationary core. lThe lower end of the tube H extends downwardly through the base or stand C, and is held in position by three light and flexible straps, N.

The diaphragm l, I prefer to maire of aluminium, and the straps N maybe of the same material, though rolled much thinner. Any other elastic substance may, however, be used for the diaphragm. The moving parts, comprising the tube H and its armatures, should be comparatively light and the armatures small in proportion to the sections F, in order that such moving parts may have as little in ertia as possible.

In using this instrument the inner coil, D,

ICO

is included in a circuitfrom a small local battery, XV, with just suflicient current to mag@ netize the core. IThe other coil,E,is connected up in the line L. The effect oi' the current llowing through the coil D is to magnetize both the sections F of the stationary core and the armatures contained within them, and, by reason of their relative positions, to impart the same polarity to their corresponding adjacent ends. The upper end of each inner core or armature being larger than the lower, and being also somewhat nearer to the lower end of the stationary section next above, is attracted bythe core above and repelled by that surrounding it. The current impulses in the coil E, acting upon the core thus effected, tend to produce, by means of this conjoint attraction and repulsion, a movement or vibration of the inner cores or armatures in line with their axis, which vibrations being inrparted to the diaphragm reproduce soundwaves correspomling to those producing the impulses.

l find that I can in this way produce a receiver of great eilioiency, which will articulate distinctly and audibly, and which is admirably well adapted for long-distance telephoning.

The superior results obtained by this instrument l attribute to a mode of operation brought about by the novel construction and relations of the parts described.

By dividing up the movable armature into several parts in fixed relation to each other, as into the sections G, not only is the conjoint effect in producing vibrations of the diaphragm increased, but the moving parts may be made much lighter than otherwise.

The number of armatures or sections of core .may vary, as will be well understood, or a number of coils may be used in place ot' the single coil E, and the general form. of the instrument may be of any kind that will secure the same relations of the parts herein described as comprising the essential elements of t-he invention.

What I claim is- 1. ln a'telephone-receiver, t-he combination, with a diaphragm, of several. armatures in fixed relation to each other and rigidly connected to the diaphragm, a local coil for magnetizing the armatures, and a line-coil for imparting movement or vibrations to them, as herein set forth.

2. The combination, with a diaphragm, of a local magnetizing-helix and a line-helix, a

4. The combination, with a diapln'agm, of 7o a loca-l helix and stationary' core composed of magnetically-insulated tubular sections, a series of armatures supported within said tubular sections and rigidly attached to a rod or tube connected with the diaphragm, and a line or tine-wire coil surrounding the local coil, as and for the purpose set forth.

5. The combination, with two concentric coils, a stationary core composed of magnetically-insulated tubular sections, and a series of armatures within the tubular sections and rigidly connected to a light rod or tube, of an adjustable ease or holder for a diaphragm, and a diaphragm secured therein and connected rigidly with the arinature-supporting rod or tube, as set forth.

6. The combination, with the stationary core composed ot' the separated tubular sections and the movable core or series of armatures rigidly connected to a rod or tube, each armature being arranged within a corresponding section of core and having a greater mass at its upper end, of a diaphragm connected rigidly with the said rod or tube and coils surrounding the cores, as set forth.

7, In a receiving-telcphone, the combination, with a diaphragm, of a rod or tube connected therewith and held in position by flexible straps secured to the stand or base of the telephone, a stationary core and a movable core, the latter of which is carried by the rod or tube, and coils or helices slu'rounding the cores, as herein set forth.

S. In a receivilig-telephone, the combination, with a helix and a sectional stationary and sectional movable core, of a diaphragm connected rigidly with the movable core, and means for adjusting the diaphragm, as set forth.

MOSES G. FARMER. lVituesses:

Truro. Dann, lll. F. Kennis.

IOO 

